JPH06306189A - Agricultural vinyl chloride resin film - Google Patents

Abstract

PURPOSE:To provide the film which can exhibit antifogging properties for a long time without detriment to the persistency of anticlouding properties. CONSTITUTION:The film is prepared by forming recesses having a width of 5-50mum and a depth of 0.01-0.5mum throughout the entire of at least either surface of a film made from a composition comprising 100 pts.wt. vinyl chloride resin, 1.5-5wt.% anticlouding agent and 0.2-5 pts.wt. sucrose fatty acid ester.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an agricultural vinyl chloride resin film. More specifically, the performance (fog resistance) to prevent the fog phenomenon near the inner surface of the coating material.
The present invention relates to a vinyl chloride resin film for agriculture, which has an excellent ability to exert the above for a long period of time and has good transparency.

[0002]

2. Description of the Related Art In recent years, in order to enhance productivity and marketability of useful plants, useful plants are forcibly, semi-forcibly or restrained grown under a coating with an agricultural coating material such as a vinyl chloride resin film for agriculture. So-called greenhouse cultivation and tunnel cultivation are actively carried out. A vinyl chloride resin film is often used as a material for covering the house or the tunnel because of its excellent weather resistance, transparency, heat retention and strength.

Most of vinyl chloride resin films currently used promote the flow of water droplets on the inner surface of the covering material (referred to as the surface facing the inside of a house or tunnel), and further increase the incident amount of sunlight. In order to increase the amount, an antifogging agent (mainly sorbitan fatty acid ester; glycerin fatty acid ester, etc.), which is a kind of surfactant, is included. Under the coating of the coating material containing such an antifogging agent, when the temperature difference between the inside and outside of the coating material becomes large, a phenomenon that fog is generated near the inner surface of the coating material is often observed.

In order to prevent the generation of fog on the inner surface of the coating material, a method has been proposed in which an antifogging agent and a fluorine-containing compound or an antifogging agent and a silicon compound are used in combination. However, when a combination of an antifogging agent and a fluorine-containing compound or a silicon-based compound is used, the antifogging property may be adversely affected, especially when the temperature is high in summer, or when it is used from the beginning of autumn. In some cases, the deterioration of the antifogging property is promoted, and the antifogging durability may be remarkably inferior. By reducing the compounding amount of the fluorine-containing compound or the silicon-based compound, it is possible to reduce the adverse effect on the antifogging property, but the effect of preventing fog is not satisfactory, and it is used for a particularly long time. In this case, the fog resistance is significantly reduced.

[0005]

Under the circumstances, the inventors of the present invention have developed a vinyl chloride resin film for agriculture which exhibits antifog property for a long period of time without lowering antifogging sustainability. As a result of diligent studies aimed at providing it, as a result of incorporating a sucrose fatty acid ester and making the film surface have a special shape, the fog-proof property can be prolonged without impairing the performance such as anti-fog property and transparency. The present invention has been completed by discovering that it will be exerted over a period of time.

[0006]

However, the gist of the present invention lies in that a resin composition containing 1.5 to 5 parts by weight of an antifogging agent and 0.2 to 5 parts by weight of a sucrose fatty acid ester is used. Width of 5 to 5 across at least one side of the film
The present invention resides in an agricultural vinyl chloride resin film having a recess of 0 μm and a depth of 0.01 to 0.5 μm. Less than,
The present invention will be described in detail.

In the present invention, the vinyl chloride resin means polyvinyl chloride, a copolymer of vinyl chloride as a main component with another comonomer, a mixture thereof, or a mixture of these with another polymer or copolymer. Say. As the antifogging agent in the present invention, various antifogging agents which are usually blended in agricultural vinyl chloride resin films can be used. Specific examples include sorbitan monostearate, sorbitan monopalmitate, sorbitan monobehenate and other sorbitan fatty acid esters; glycerin monolaurate, diglycerin monopalmitate, glycerin monostearate and other glycerin fatty acid esters. To be

These antifogging agents may be used alone or in combination of two or more kinds. The amount of the antifogging agent to be added to the base resin is 100 parts by weight of the vinyl chloride resin,
It is in the range of 1.5 to 5 parts by weight. When it is less than 1.5 parts by weight, the antifogging effect of the film becomes insufficient, and when it is more than 5 parts by weight, bleeding out on the film surface is not preferable.

The sucrose fatty acid ester used in the present invention is obtained by esterifying sucrose and a fatty acid by a known method. Specific examples thereof include sucrose stearate, sucrose palmitate, sucrose oleate, and sucrose laurate, with HLB preferably 5-18. These sucrose fatty acid esters may be used alone or in combination of two or more. The amount of the sucrose fatty acid ester to be added to the base resin is 0.2 to 5 parts by weight per 100 parts by weight of the vinyl chloride resin. If the amount is less than 0.2 parts by weight, the effect of preventing fog formation is insufficient, and if it exceeds 5 parts by weight, bleeding out to the film surface may occur, which is not preferable.

Further, 30 to 70 parts by weight of a commonly used plasticizer is added to 100 parts by weight of the vinyl chloride resin as a base material. If necessary, additives such as a heat stabilizer, a lubricant, a light stabilizer, an ultraviolet absorber, and a colorant, which are usually added to a vinyl chloride resin, are contained in a usual content, for example, a vinyl chloride resin 100. It can be contained in a small amount of 10 parts by weight or less with respect to parts by weight.

The required amount of each resin composition is weighed and blended using a ribbon blender, a Banbury mixer, a super mixer, and other blending machines and blenders. Then, the obtained composition is subjected to a method known per se, for example, the T-die method,
It is formed into a film by a melt extrusion molding method such as an inflation method, a calender molding method, a solution casting method, or the like. If the thickness of the film is too thin, the strength for agricultural use is not sufficient, and if it is too thick, it is inconvenient for the work of forming a film and the subsequent cutting, bonding, spreading and the like. A range of 2 mm is preferable.

According to the present invention, a predetermined concave portion is formed on the surface of the film made of the above substrate. To form recesses on the surface of the film, ion beam etching, photoetching (combination of photoresist and etching), photoelectroforming (combination of photoresist and electroforming), or even direct processing by laser irradiation, or Alternatively, a method of embossing after forming an uneven metal mold by cutting or the like may be used.

The shape of the depressions on the surface of the vinyl chloride resin film may be groove-like or depression-like, but the width of the depressions is 5 to 50 μm, and the depth of the depressions is 0.
It is necessary to set it to 01 to 0.5 μm. In particular, the width of the recess is 5 to 30 μm, and the depth of the recess is 0.01 to 0.
It is preferably in the range of 3 μm. The width of the recess is 50μ
If it exceeds m or the depth is less than 0.01 μm,
The function of preventing fog formation near the surface of the film is reduced, and when the width of the recesses is less than 5 μm, the fog prevention ability tends to decrease with time. Further, if the depth exceeds 0.5 μm, the transparency decreases. When the transparency is lowered, there is a drawback that the crops inside the house cannot be seen from the outside.

When the recesses are formed in the shape of grooves, the arrangement on the film surface may be parallel, concentric, spiral, latticed, or the like. In the case of forming a depression, the shape on the surface of the covering material may be a circle, an ellipse, a triangle, a quadrangle, or the like, and each depression may be independent, but it is preferable to disperse them uniformly. The ratio of the recessed area to the surface where the recessed portion is formed is preferably 50% or more from the viewpoint of the fog generation preventing ability.

The depressions on the surface of the film may be formed on both sides or only on one side depending on the usage of the film. A film in which the recesses are linear grooves formed in parallel with each other and whose groove has a V-shaped or U-shaped cross-section is easier to manufacture than other types of films, and thus is recommended.

When the vinyl chloride resin film for agriculture according to the present invention is spread on an agricultural house, a tunnel or the like, it is spread with the surface having the recesses formed inside. When a predetermined concave portion is formed on the inner surface of the film, water droplets are easily condensed in the concave portion, so that it is possible to prevent fog from occurring near the inner surface of the film. Further, the presence of the concave portions also improves the antifogging sustainability. In addition, it is preferable to improve the dustproof property of the outer surface of the stretched film. In order to improve the dustproof property, it is preferable to form a dustproof film based on a solvent paint, a water-soluble paint, an ultraviolet curable paint or the like.

[0017]

EXAMPLES The present invention will be described in detail below based on examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Examples 1-2, Comparative Examples 1-6 I. Production of film 100 parts by weight of polyvinyl chloride (average degree of polymerization 1300),
45 parts by weight of di-2-ethylhexyl phthalate, 5 parts by weight of tricresyl phosphate, 1 part by weight of epoxy resin plasticizer (trade name Epicoat 828), 1 part by weight of barium-zinc composite liquid stabilizer, 0.2 barium stearate.
By weight, 0.4 parts by weight of zinc stearate and 2.0 parts by weight of sorbitan monostearate (anti-fog agent) are used as a basic composition, and a predetermined amount of sucrose fatty acid ester or the like shown in Table 1 is added thereto. The resulting composition was supplied to a calender roll heated to 180 ° C. to form a film having a thickness of 0.1 mm.

II. Formation of Recesses An embossing roll having a shape shown in FIG. 1 and having a pitch and a grain height of 210 mm in diameter shown in Table 1 was prepared by photoetching and used as a water-cooled embossing roll. The film produced in the above item I heated to a predetermined temperature with an infrared heater is placed between the water-cooled embossing roll and the water-cooled rubber roll by 0.2
Embossing was performed by passing the pressure so that the pressure was kg / cm to form a recess on one surface. Regarding the grain shape of the film, the atomic force microscope (SF, manufactured by Seiko Instruments Inc.)
A300), and the area ratio of the concave region was calculated by the power spectrum. The respective film shapes are shown in Table-1.

III. Evaluation of film <Fog generation test> A frontage of 5.4 m in a field in Isshi-gun, Mie prefecture,
Eight pipe houses with a ridge height of 3 m and a depth of 15 m were constructed, and each ridge was coated with one kind of the above-mentioned film with the concave portion inside.
For the evaluation of the degree of fog generation, the pipe house was coated with the film for 5 days (October 19 to October 23, 1992) and for the 5 days after 4 months had passed (1 18th to 22nd of January) and 5 days after 6 months from the coating (15th of March to 19th of March, 1993).

The numerical values of "evaluation of fog generation" have the following meanings. "1": No fog was found in the house, or a very small amount was generated near the inner surface of the film. “2”: Fog is generated over the entire house, but the back of the house 15 m ahead can be clearly identified. “3”: A state where fog was generated in the entire house with a slight amount of fog and the inside of the house 15 m ahead could not be clearly identified. "4": The fog was heavily generated over the entire house, and the inside of the house 15 m ahead could not be identified at all. Show the average value of the values for 5 days when the fog generation situation was observed.
Shown in 2.

<Evaluation of antifogging property> In a field in Nagoya City, Aichi Prefecture,
A single roof house with a frontage of 2 m, a building height of 2 m, and a depth of 30 m was coated with the above-mentioned 8 types of films on September 17, 1992 with the concave part on the inside, and the anti-fog property of each film was observed with the naked eye periodically And evaluated. The results are shown in Table-2. The numerical values of "evaluation of antifogging property" have the following meanings. “1”: Water adhered in a thin film form, and no water droplet was observed. “2”: Water adhered in a thin film, but slightly large water droplets were observed. “3”: A state in which fine water droplets are partially adhered. "4": A state where fine water droplets are observed to be attached to the entire film surface.

<Evaluation of Transparency> The straight-line light transmittance of the light rays having a wavelength of 555 nm of the eight kinds of films was measured by a spectrophotometer (Model 323 manufactured by Hitachi, Ltd.). This linear light transmittance means that the closer to 90% which is the transmittance of the film in which the concave portion is not formed, the more transparent the film. The evaluation results are shown in Table-2.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

The agricultural vinyl chloride resin film of the present invention has the effect of preventing the fog generation phenomenon in the vicinity of the film surface for a long period of time, and further has the original transparency of the film, and is relatively transparent. When the film is stretched in early autumn, which is an early stage, the anti-fogging property during winter and early spring does not significantly decrease, and the utility value as an agricultural film is extremely large.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of the surface of an embossing roll used in an example.

[Explanation of symbols]

 P pitch h grain height

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area C08L 27/06 KGY 9166-4J

Claims (2)

[Claims] 1. An antifogging agent of 1.5 to 5 parts by weight and a sucrose fatty acid ester of 0.1 to 100 parts by weight per 100 parts by weight of a vinyl chloride resin.
A width of 5 to 50 μm and a depth of 0.0 across the entire surface of at least one side of a film made of a resin composition containing 2 to 5 parts by weight.
A vinyl chloride resin film for agriculture, having a recessed portion of 1 to 0.5 μm formed therein. 2. The agricultural vinyl chloride resin film according to claim 1, wherein the total area of the recessed regions is 50% or more of the area of the film surface on which the recesses are formed.